1. Field of the Invention
This invention relates to an ink jet head which performs recording by jetting liquid to form flying droplets, a method for preparing the head, and an orifice plate provided with discharge ports (orifices) for jetting liquid which is equipped on the head.
2. Related Background Art
An ink jet recording head is constituted basically of a discharge port plate, the so called orifice plate, having discharge ports for ink (orifices), a ceiling plate having concavities for forming ink pathways communicated with the respective orifices, and a substrate constituting a part of the liquid pathways and having an energy generating member which generates energy to be utilized for discharging ink.
The orifice for discharging ink affects discharge speed and discharge direction of the ink droplets, and therefore its precision, shape and the like are important. Above all, the shape of the portion where the liquid pathway and the orifice are communicated with each other and the shape of the orifice should be desirably determined so as to make the ink flow smoothly. However, in the ink jet recoding head according to the background art, the schematic sectional view of which is shown in FIG. 2, the following problems occurred in some cases. That is, because the sizes of the liquid pathway and the orifice are different at the communicated portion of the liquid pathway 6 and the orifice 5, the flow of ink is not smooth, which reduces the discharging speed. This causes the problem that the discharging speed is lowered to worsen the precision of shooting points, leading sometimes to deterioration of printing quality. Also, the shape of the orifice should be preferably such that it is tapered, becoming gradually narrowed toward the tip end, for improving discharging performance, but it has been also difficult to apply such working on the fine orifices of an ink jet recording head having an orifice plate with a small thickness.